An electrical energy transmission system for transmitting a generated three-phase current conventionally includes a three-phase electrical power generator and an electrical transmission line which transmits the generated electrical energy to a load.
There were attempts to carry out the electrical energy transmission by means of one wire. First applications of the single-wire electrical energy transmission were disclosed by Nikola Tesla in U.S. Pat. No. 593,138 and in British Patent No. 8,200. Another single line transmission technique is known as the Goubau line or G-line, which is a type of single wire transmission line used at UHF and microwave frequencies (see Geog Goubau, “Surface waves and their Application to Transmission Lines,” Journal of Applied Physics, Volume 21, November, 1950). However, a G-line is a type of waveguide, rather than a wire for an electric circuit. There was also an experiment based on U.S. Pat. No. 6,104,107 to Avramenko et al. All these concepts were based on signal processing, including frequency converting or signal straightening. They however negatively influence the process of transmission of electrical energy and lead to loss of power.
Also an electrical energy distribution method is known with the use of one conductor, however with a return of the electrical current through earth, according to the authors of the proposed method. This method is known as the Single Wire Earth Return (SWER). However, the simplification of the electrical energy transfer in this system is achieved due to the loss of a part of the power produced by the source. One of the reasons for the loss of power is the reactive power caused by the imbalance of the line, and this loss depends on the length of the line.
There are three-phase electrical energy transmission systems which have significant advantages associated with high efficiency of generators and motors. Conventional three-phase electrical energy transmission systems transmit electrical energy through three or four wires. However, the presence of three or four wires and also of large masts in not the only drawback of these systems. Another drawback is a line voltage between two wires in this system at the root of the three phase voltage. This may have negative consequences, such a corona effect and additional losses in the lines. Additional disadvantage of the three phase system is the need to arrange the wires at a distance of several meters from each other. This in turn makes difficult to use underground lines.